/*
** $Id: lobject.c,v 2.113 2016/12/22 13:08:50 roberto Exp $
** Some generic functions over Lua objects
** See Copyright Notice in lua.h
*/

#define lobject_c
#define LUA_CORE

#include "lprefix.h"


#include <locale.h>
#include <math.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "lua.h"

#include "lctype.h"
#include "ldebug.h"
#include "ldo.h"
#include "lmem.h"
#include "lobject.h"
#include "lstate.h"
#include "lstring.h"
#include "lvm.h"



LUAI_DDEF const TValue luaO_nilobject_ = {NILCONSTANT};


/*
** converts an integer to a "floating point byte", represented as
** (eeeeexxx), where the real value is (1xxx) * 2^(eeeee - 1) if
** eeeee != 0 and (xxx) otherwise.
*/
int luaO_int2fb( unsigned int x ) {
    int e = 0;  /* exponent */

    if ( x < 8 ) {
        return x;
    }

    while ( x >= ( 8 << 4 ) ) { /* coarse steps */
        x = ( x + 0xf ) >> 4; /* x = ceil(x / 16) */
        e += 4;
    }

    while ( x >= ( 8 << 1 ) ) { /* fine steps */
        x = ( x + 1 ) >> 1; /* x = ceil(x / 2) */
        e++;
    }

    return ( ( e + 1 ) << 3 ) | ( cast_int( x ) - 8 );
}


/* converts back */
int luaO_fb2int( int x ) {
    return ( x < 8 ) ? x : ( ( x & 7 ) + 8 ) << ( ( x >> 3 ) - 1 );
}


/*
** Computes ceil(log2(x))
*/
int luaO_ceillog2( unsigned int x ) {
    static const lu_byte log_2[256] =    /* log_2[i] = ceil(log2(i - 1)) */
    {
        0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
        6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
        7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
        8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8
    };
    int l = 0;
    x--;

    while ( x >= 256 ) {
        l += 8;
        x >>= 8;
    }

    return l + log_2[x];
}


static lua_Integer intarith( lua_State* L, int op, lua_Integer v1,
                             lua_Integer v2 ) {
    switch ( op ) {
    case LUA_OPADD:
        return intop( +, v1, v2 );

    case LUA_OPSUB:
        return intop( -, v1, v2 );

    case LUA_OPMUL:
        return intop( *, v1, v2 );

    case LUA_OPMOD:
        return luaV_mod( L, v1, v2 );

    case LUA_OPIDIV:
        return luaV_div( L, v1, v2 );

    case LUA_OPBAND:
        return intop( &, v1, v2 );

    case LUA_OPBOR:
        return intop( |, v1, v2 );

    case LUA_OPBXOR:
        return intop( ^, v1, v2 );

    case LUA_OPSHL:
        return luaV_shiftl( v1, v2 );

    case LUA_OPSHR:
        return luaV_shiftl( v1, -v2 );

    case LUA_OPUNM:
        return intop( -, 0, v1 );

    case LUA_OPBNOT:
        return intop( ^, ~l_castS2U( 0 ), v1 );

    default:
        lua_assert( 0 );
        return 0;
    }
}


static lua_Number numarith( lua_State* L, int op, lua_Number v1,
                            lua_Number v2 ) {
    switch ( op ) {
    case LUA_OPADD:
        return luai_numadd( L, v1, v2 );

    case LUA_OPSUB:
        return luai_numsub( L, v1, v2 );

    case LUA_OPMUL:
        return luai_nummul( L, v1, v2 );

    case LUA_OPDIV:
        return luai_numdiv( L, v1, v2 );

    case LUA_OPPOW:
        return luai_numpow( L, v1, v2 );

    case LUA_OPIDIV:
        return luai_numidiv( L, v1, v2 );

    case LUA_OPUNM:
        return luai_numunm( L, v1 );

    case LUA_OPMOD: {
        lua_Number m;
        luai_nummod( L, v1, v2, m );
        return m;
    }

    default:
        lua_assert( 0 );
        return 0;
    }
}


void luaO_arith( lua_State* L, int op, const TValue* p1, const TValue* p2,
                 TValue* res ) {
    switch ( op ) {
    case LUA_OPBAND:
    case LUA_OPBOR:
    case LUA_OPBXOR:
    case LUA_OPSHL:
    case LUA_OPSHR:
    case LUA_OPBNOT: {  /* operate only on integers */
        lua_Integer i1;
        lua_Integer i2;

        if ( tointeger( p1, &i1 ) && tointeger( p2, &i2 ) ) {
            setivalue( res, intarith( L, op, i1, i2 ) );
            return;
        }
        else {
            break;    /* go to the end */
        }
    }

    case LUA_OPDIV:
    case LUA_OPPOW: {  /* operate only on floats */
        lua_Number n1;
        lua_Number n2;

        if ( tonumber( p1, &n1 ) && tonumber( p2, &n2 ) ) {
            setfltvalue( res, numarith( L, op, n1, n2 ) );
            return;
        }
        else {
            break;    /* go to the end */
        }
    }

    default: {  /* other operations */
        lua_Number n1;
        lua_Number n2;

        if ( ttisinteger( p1 ) && ttisinteger( p2 ) ) {
            setivalue( res, intarith( L, op, ivalue( p1 ), ivalue( p2 ) ) );
            return;
        }
        else if ( tonumber( p1, &n1 ) && tonumber( p2, &n2 ) ) {
            setfltvalue( res, numarith( L, op, n1, n2 ) );
            return;
        }
        else {
            break;    /* go to the end */
        }
    }
    }

    /* could not perform raw operation; try metamethod */
    lua_assert( L != NULL ); /* should not fail when folding (compile time) */
    luaT_trybinTM( L, p1, p2, res, cast( TMS, ( op - LUA_OPADD ) + TM_ADD ) );
}


int luaO_hexavalue( int c ) {
    if ( lisdigit( c ) ) {
        return c - '0';
    }
    else {
        return ( ltolower( c ) - 'a' ) + 10;
    }
}


static int isneg( const char** s ) {
    if ( **s == '-' ) {
        ( *s )++;
        return 1;
    }
    else if ( **s == '+' ) {
        ( *s )++;
    }

    return 0;
}



/*
** {==================================================================
** Lua's implementation for 'lua_strx2number'
** ===================================================================
*/

#if !defined(lua_strx2number)

/* maximum number of significant digits to read (to avoid overflows
   even with single floats) */
#define MAXSIGDIG   30

/*
** convert an hexadecimal numeric string to a number, following
** C99 specification for 'strtod'
*/
static lua_Number lua_strx2number( const char* s, char** endptr ) {
    int dot = lua_getlocaledecpoint();
    lua_Number r = 0.0;  /* result (accumulator) */
    int sigdig = 0;  /* number of significant digits */
    int nosigdig = 0;  /* number of non-significant digits */
    int e = 0;  /* exponent correction */
    int neg;  /* 1 if number is negative */
    int hasdot = 0;  /* true after seen a dot */
    *endptr = cast( char*, s ); /* nothing is valid yet */

    while ( lisspace( cast_uchar( *s ) ) ) {
        s++;    /* skip initial spaces */
    }

    neg = isneg( &s ); /* check signal */

    if ( !( *s == '0' && ( *( s + 1 ) == 'x' ||
                           *( s + 1 ) == 'X' ) ) ) { /* check '0x' */
        return 0.0;    /* invalid format (no '0x') */
    }

    for ( s += 2; ; s++ ) { /* skip '0x' and read numeral */
        if ( *s == dot ) {
            if ( hasdot ) {
                break;    /* second dot? stop loop */
            }
            else {
                hasdot = 1;
            }
        }
        else if ( lisxdigit( cast_uchar( *s ) ) ) {
            if ( sigdig == 0 && *s == '0' ) { /* non-significant digit (zero)? */
                nosigdig++;
            }
            else if ( ++sigdig <= MAXSIGDIG ) { /* can read it without overflow? */
                r = ( r * cast_num( 16.0 ) ) + luaO_hexavalue( *s );
            }
            else {
                e++;    /* too many digits; ignore, but still count for exponent */
            }

            if ( hasdot ) {
                e--;    /* decimal digit? correct exponent */
            }
        }
        else {
            break;    /* neither a dot nor a digit */
        }
    }

    if ( nosigdig + sigdig == 0 ) { /* no digits? */
        return 0.0;    /* invalid format */
    }

    *endptr = cast( char*, s ); /* valid up to here */
    e *= 4;  /* each digit multiplies/divides value by 2^4 */

    if ( *s == 'p' || *s == 'P' ) { /* exponent part? */
        int exp1 = 0;  /* exponent value */
        int neg1;  /* exponent signal */
        s++;  /* skip 'p' */
        neg1 = isneg( &s ); /* signal */

        if ( !lisdigit( cast_uchar( *s ) ) ) {
            return 0.0;    /* invalid; must have at least one digit */
        }

        while ( lisdigit( cast_uchar( *s ) ) ) { /* read exponent */
            exp1 = exp1 * 10 + *( s++ ) - '0';
        }

        if ( neg1 ) {
            exp1 = -exp1;
        }

        e += exp1;
        *endptr = cast( char*, s ); /* valid up to here */
    }

    if ( neg ) {
        r = -r;
    }

    return l_mathop( ldexp )( r, e );
}

#endif
/* }====================================================== */


/* maximum length of a numeral */
#if !defined (L_MAXLENNUM)
#define L_MAXLENNUM 200
#endif

static const char* l_str2dloc( const char* s, lua_Number* result, int mode ) {
    char* endptr;
    *result = ( mode == 'x' ) ? lua_strx2number( s, &endptr ) /* try to convert */
              : lua_str2number( s, &endptr );

    if ( endptr == s ) {
        return NULL;    /* nothing recognized? */
    }

    while ( lisspace( cast_uchar( *endptr ) ) ) {
        endptr++;    /* skip trailing spaces */
    }

    return ( *endptr == '\0' ) ? endptr : NULL; /* OK if no trailing characters */
}


/*
** Convert string 's' to a Lua number (put in 'result'). Return NULL
** on fail or the address of the ending '\0' on success.
** 'pmode' points to (and 'mode' contains) special things in the string:
** - 'x'/'X' means an hexadecimal numeral
** - 'n'/'N' means 'inf' or 'nan' (which should be rejected)
** - '.' just optimizes the search for the common case (nothing special)
** This function accepts both the current locale or a dot as the radix
** mark. If the convertion fails, it may mean number has a dot but
** locale accepts something else. In that case, the code copies 's'
** to a buffer (because 's' is read-only), changes the dot to the
** current locale radix mark, and tries to convert again.
*/
static const char* l_str2d( const char* s, lua_Number* result ) {
    const char* endptr;
    const char* pmode = strpbrk( s, ".xXnN" );
    int mode = pmode ? ltolower( cast_uchar( *pmode ) ) : 0;

    if ( mode == 'n' ) { /* reject 'inf' and 'nan' */
        return NULL;
    }

    endptr = l_str2dloc( s, result, mode ); /* try to convert */

    if ( endptr == NULL ) { /* failed? may be a different locale */
        char buff[L_MAXLENNUM + 1];
        const char* pdot = strchr( s, '.' );

        if ( strlen( s ) > L_MAXLENNUM || pdot == NULL ) {
            return NULL;    /* string too long or no dot; fail */
        }

        strcpy( buff, s ); /* copy string to buffer */
        buff[pdot - s] = lua_getlocaledecpoint();  /* correct decimal point */
        endptr = l_str2dloc( buff, result, mode ); /* try again */

        if ( endptr != NULL ) {
            endptr = s + ( endptr - buff );    /* make relative to 's' */
        }
    }

    return endptr;
}


#define MAXBY10     cast(lua_Unsigned, LUA_MAXINTEGER / 10)
#define MAXLASTD    cast_int(LUA_MAXINTEGER % 10)

static const char* l_str2int( const char* s, lua_Integer* result ) {
    lua_Unsigned a = 0;
    int empty = 1;
    int neg;

    while ( lisspace( cast_uchar( *s ) ) ) {
        s++;    /* skip initial spaces */
    }

    neg = isneg( &s );

    if ( s[0] == '0' &&
            ( s[1] == 'x' || s[1] == 'X' ) ) { /* hex? */
        s += 2;  /* skip '0x' */

        for ( ; lisxdigit( cast_uchar( *s ) ); s++ ) {
            a = a * 16 + luaO_hexavalue( *s );
            empty = 0;
        }
    }
    else {   /* decimal */
        for ( ; lisdigit( cast_uchar( *s ) ); s++ ) {
            int d = *s - '0';

            if ( a >= MAXBY10 && ( a > MAXBY10 || d > MAXLASTD + neg ) ) { /* overflow? */
                return NULL;    /* do not accept it (as integer) */
            }

            a = a * 10 + d;
            empty = 0;
        }
    }

    while ( lisspace( cast_uchar( *s ) ) ) {
        s++;    /* skip trailing spaces */
    }

    if ( empty || *s != '\0' ) {
        return NULL;    /* something wrong in the numeral */
    }
    else {
        *result = l_castU2S( ( neg ) ? 0u - a : a );
        return s;
    }
}


size_t luaO_str2num( const char* s, TValue* o ) {
    lua_Integer i;
    lua_Number n;
    const char* e;

    if ( ( e = l_str2int( s, &i ) ) != NULL ) { /* try as an integer */
        setivalue( o, i );
    }
    else if ( ( e = l_str2d( s, &n ) ) != NULL ) { /* else try as a float */
        setfltvalue( o, n );
    }
    else {
        return 0;    /* conversion failed */
    }

    return ( e - s ) + 1; /* success; return string size */
}


int luaO_utf8esc( char* buff, unsigned long x ) {
    int n = 1;  /* number of bytes put in buffer (backwards) */
    lua_assert( x <= 0x10FFFF );

    if ( x < 0x80 ) { /* ascii? */
        buff[UTF8BUFFSZ - 1] = cast( char, x );
    }
    else {  /* need continuation bytes */
        unsigned int mfb = 0x3f;  /* maximum that fits in first byte */

        do {  /* add continuation bytes */
            buff[UTF8BUFFSZ - ( n++ )] = cast( char, 0x80 | ( x & 0x3f ) );
            x >>= 6;  /* remove added bits */
            mfb >>= 1;  /* now there is one less bit available in first byte */
        }
        while ( x > mfb );   /* still needs continuation byte? */

        buff[UTF8BUFFSZ - n] = cast( char, ( ~mfb << 1 ) | x ); /* add first byte */
    }

    return n;
}


/* maximum length of the conversion of a number to a string */
#define MAXNUMBER2STR   50


/*
** Convert a number object to a string
*/
void luaO_tostring( lua_State* L, StkId obj ) {
    char buff[MAXNUMBER2STR];
    size_t len;
    lua_assert( ttisnumber( obj ) );

    if ( ttisinteger( obj ) ) {
        len = lua_integer2str( buff, sizeof( buff ), ivalue( obj ) );
    }
    else {
        len = lua_number2str( buff, sizeof( buff ), fltvalue( obj ) );
#if !defined(LUA_COMPAT_FLOATSTRING)

        if ( buff[strspn( buff, "-0123456789" )] == '\0' ) { /* looks like an int? */
            buff[len++] = lua_getlocaledecpoint();
            buff[len++] = '0';  /* adds '.0' to result */
        }

#endif
    }

    setsvalue2s( L, obj, luaS_newlstr( L, buff, len ) );
}


static void pushstr( lua_State* L, const char* str, size_t l ) {
    setsvalue2s( L, L->top, luaS_newlstr( L, str, l ) );
    luaD_inctop( L );
}


/*
** this function handles only '%d', '%c', '%f', '%p', and '%s'
   conventional formats, plus Lua-specific '%I' and '%U'
*/
const char* luaO_pushvfstring( lua_State* L, const char* fmt, va_list argp ) {
    int n = 0;

    for ( ;; ) {
        const char* e = strchr( fmt, '%' );

        if ( e == NULL ) {
            break;
        }

        pushstr( L, fmt, e - fmt );

        switch ( *( e + 1 ) ) {
        case 's': {  /* zero-terminated string */
            const char* s = va_arg( argp, char* );

            if ( s == NULL ) {
                s = "(null)";
            }

            pushstr( L, s, strlen( s ) );
            break;
        }

        case 'c': {  /* an 'int' as a character */
            char buff = cast( char, va_arg( argp, int ) );

            if ( lisprint( cast_uchar( buff ) ) ) {
                pushstr( L, &buff, 1 );
            }
            else { /* non-printable character; print its code */
                luaO_pushfstring( L, "<\\%d>", cast_uchar( buff ) );
            }

            break;
        }

        case 'd': {  /* an 'int' */
            setivalue( L->top, va_arg( argp, int ) );
            goto top2str;
        }

        case 'I': {  /* a 'lua_Integer' */
            setivalue( L->top, cast( lua_Integer, va_arg( argp, l_uacInt ) ) );
            goto top2str;
        }

        case 'f': {  /* a 'lua_Number' */
            setfltvalue( L->top, cast_num( va_arg( argp, l_uacNumber ) ) );
top2str:  /* convert the top element to a string */
            luaD_inctop( L );
            luaO_tostring( L, L->top - 1 );
            break;
        }

        case 'p': {  /* a pointer */
            char buff[4 * sizeof( void* ) + 8]; /* should be enough space for a '%p' */
            int l = l_sprintf( buff, sizeof( buff ), "%p", va_arg( argp, void* ) );
            pushstr( L, buff, l );
            break;
        }

        case 'U': {  /* an 'int' as a UTF-8 sequence */
            char buff[UTF8BUFFSZ];
            int l = luaO_utf8esc( buff, cast( long, va_arg( argp, long ) ) );
            pushstr( L, buff + UTF8BUFFSZ - l, l );
            break;
        }

        case '%': {
            pushstr( L, "%", 1 );
            break;
        }

        default: {
            luaG_runerror( L, "invalid option '%%%c' to 'lua_pushfstring'",
                           *( e + 1 ) );
        }
        }

        n += 2;
        fmt = e + 2;
    }

    luaD_checkstack( L, 1 );
    pushstr( L, fmt, strlen( fmt ) );

    if ( n > 0 ) {
        luaV_concat( L, n + 1 );
    }

    return svalue( L->top - 1 );
}


const char* luaO_pushfstring( lua_State* L, const char* fmt, ... ) {
    const char* msg;
    va_list argp;
    va_start( argp, fmt );
    msg = luaO_pushvfstring( L, fmt, argp );
    va_end( argp );
    return msg;
}


/* number of chars of a literal string without the ending \0 */
#define LL(x)   (sizeof(x)/sizeof(char) - 1)

#define RETS    "..."
#define PRE "[string \""
#define POS "\"]"

#define addstr(a,b,l)   ( memcpy(a,b,(l) * sizeof(char)), a += (l) )

void luaO_chunkid( char* out, const char* source, size_t bufflen ) {
    size_t l = strlen( source );

    if ( *source == '=' ) { /* 'literal' source */
        if ( l <= bufflen ) { /* small enough? */
            memcpy( out, source + 1, l * sizeof( char ) );
        }
        else {  /* truncate it */
            addstr( out, source + 1, bufflen - 1 );
            *out = '\0';
        }
    }
    else if ( *source == '@' ) {   /* file name */
        if ( l <= bufflen ) { /* small enough? */
            memcpy( out, source + 1, l * sizeof( char ) );
        }
        else {  /* add '...' before rest of name */
            addstr( out, RETS, LL( RETS ) );
            bufflen -= LL( RETS );
            memcpy( out, source + 1 + l - bufflen, bufflen * sizeof( char ) );
        }
    }
    else {   /* string; format as [string "source"] */
        const char* nl = strchr( source, '\n' ); /* find first new line (if any) */
        addstr( out, PRE, LL( PRE ) ); /* add prefix */
        bufflen -= LL( PRE RETS POS ) + 1; /* save space for prefix+suffix+'\0' */

        if ( l < bufflen && nl == NULL ) { /* small one-line source? */
            addstr( out, source, l ); /* keep it */
        }
        else {
            if ( nl != NULL ) {
                l = nl - source;    /* stop at first newline */
            }

            if ( l > bufflen ) {
                l = bufflen;
            }

            addstr( out, source, l );
            addstr( out, RETS, LL( RETS ) );
        }

        memcpy( out, POS, ( LL( POS ) + 1 ) * sizeof( char ) );
    }
}

